Scientists have issued a warning about the health of another killer whale that lives in the Salish Sea.

Images released by the National Oceanic and Atmospheric Administration show that a female mother, J37, has a reduction in fat around her head.

"Her condition is contrasted to September 2018, when she was also very lean but had not yet developed such an obvious 'peanut head', and to September 2015 when she was clearly pregnant (note width at mid body) and in peak recent condition," the U.S. government agency states on its website.

The images were taken with a remotely piloted drone and were obtained by NOAA's John Durban and Holly Fearnbach of Sealife Response, Rehabilitation, and Research.

The photos also reveal that J17's three-and-a-half-year-old daughter, J53, is in declining health.

There are only 75 southern resident orcas remaining in the Salish Sea.NOAA

"NOAA Fisheries does not plan to intervene with J17 or J53 at this time but will continue to work with partners to gather additional information, evaluate options and consult with experts," the website states. "The public can help Southern Resident killer whales by giving them space to forage undisturbed and respecting the mandated state and federal viewing distances. NOAA Fisheries is also working with researchers to closely coordinate and limit their approaches around these whales."

NOAA has listed orcas as endangered.

According to Orca Network, there are only 75 southern resident orcas living in three pods in the Salish Sea.

Orca Network states on its website that 41 southern resident orcas have been born and survived since 1998. The most recent was in January in L pod, which was the first calf to survive after birth since November 2015.

These orcas can life up to 90 years, weigh up to 11 tons, and grow to a length of nearly 10 metres.

NOAA states that these marine mammals in the three pods are threated by a shortage of food—particularly chinook salmon—as well by as entanglement, chemical contaminants, disturbances from vessel traffic, and oil spills.

Video of Recovering the Southern Resident Killer Whale with Research and Conservation

NOAA released this educational video in 2017 about the recent history of the southern resident orcas,NOAA

In 2017, a research paper published in Scientific Reports concluded that the southern resident orcas have a 25 percent chance of going extinct in the next century.

"Prey limitation is the most important factor affecting population growth," the paper stated. "However, to meet recovery targets through prey management alone, Chinook abundance would have to be sustained near the highest levels since the 1970s."

Under Washington state law, boats must remain at least 300 yards from southern resident orcas and 400 yards from their path and slow to seven knots within a half-mile of them.

In June, vessels on the Canadian side of the border will have to remain at least 400 metres away, according to a new regulation announced by the Trudeau government.

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